Cretaceous and Neogene lavas of Sabah - origin and tectonic significance

702001-100928-725-B
Author : Shariff A.K. Omang and Sanudin Hj. Tahir
Publication : Bulletin of the Geological Society of Malaysia
Page : 21-30
Volume Number : 38
Year : 1995
DOI : https://doi.org/10.7186/bgsm38199503

Bulletin of the Geological Society of Malaysia, Volume 38, Dec. 1995, pp. 21 - 30

 

Cretaceous and Neogene lavas of Sabah - origin and tectonic significance

SHARIFF A.K. OMANG AND SANUDIN HJ. TAHIR

Jabatan Sains Bumi, Fakulti Sains dan Sumber Alam, Universiti Kebangsaan Malaysia Kampus Sabah, Beg Berkunci No. 62, 88996 Kota Kinabalu, Sabah, Malaysia

 

Abstract: A combination of field and geochemical investigations of the Cretaceous and Neogene lavas of Sabah (CNLS) allow some control on the relative timing of events in its tectono-magmatic history. The low-K tholeiitic lava (Telupid basalt of Cretaceous age) or so-called ‘boninitic suite‘, interpreted as a product of partial melting of hydrated oceanic lithosphere in the mantle wedge, suggesting that the first magma formed in response to intra-oceanic subduction. As subduction proceeded, the magma composition changed to the calc-alkaline suite (high-K calc-alkaline lavas of Neogene Tungku and Tanjung Batu andesites), probably because of the hydrated asthenosphere of the mantle wedge confirming an oceanic, supra-subduction zone origin for this volcanic arc assemblage.

An evolutionary sequence can be envisaged for the CNLS which begins with the establishment of an oceanic island arc where supra-subduction zone extension led to the genesis of tholeiitic lava and/or boninitic (Telupid basalt) and followed by formation of the volcanic arc (Tungku andesite). Next, followed by Tungku arc-splitting, as extension continued, a marginal basin (Sulu Sea) developed. Later, incomplete closing of the Sulu Sea caused the southwards subduction beneath the older arc and formation of the Tanjung Batu andesite. 

https://doi.org/10.7186/bgsm38199503